From 84adefa331c4159d432d22840663c38f155cd4c1 Mon Sep 17 00:00:00 2001
From: Erlang/OTP <otp@erlang.org>
Date: Fri, 20 Nov 2009 14:54:40 +0000
Subject: The R13B03 release.

---
 lib/erl_interface/src/registry/hash_resize.c | 67 ++++++++++++++++++++++++++++
 1 file changed, 67 insertions(+)
 create mode 100644 lib/erl_interface/src/registry/hash_resize.c

(limited to 'lib/erl_interface/src/registry/hash_resize.c')

diff --git a/lib/erl_interface/src/registry/hash_resize.c b/lib/erl_interface/src/registry/hash_resize.c
new file mode 100644
index 0000000000..9c34a0d41c
--- /dev/null
+++ b/lib/erl_interface/src/registry/hash_resize.c
@@ -0,0 +1,67 @@
+/*
+ * %CopyrightBegin%
+ * 
+ * Copyright Ericsson AB 1998-2009. All Rights Reserved.
+ * 
+ * The contents of this file are subject to the Erlang Public License,
+ * Version 1.1, (the "License"); you may not use this file except in
+ * compliance with the License. You should have received a copy of the
+ * Erlang Public License along with this software. If not, it can be
+ * retrieved online at http://www.erlang.org/.
+ * 
+ * Software distributed under the License is distributed on an "AS IS"
+ * basis, WITHOUT WARRANTY OF ANY KIND, either express or implied. See
+ * the License for the specific language governing rights and limitations
+ * under the License.
+ * 
+ * %CopyrightEnd%
+ *
+
+ */
+#include <stdlib.h>
+#include "hash.h"
+
+/* move the elements from oldtab to a new table newsize. The old table
+ * is freed and the caller should discard the pointer. On failure
+ * (i.e. if malloc fails) return the old table and do nothing. 
+*/
+ei_hash *ei_hash_resize(ei_hash *oldtab, int newsize)
+{
+  ei_hash *newtab=NULL;
+  ei_bucket *b, *next;
+  int i,h;
+
+  /* make sure size is odd, then increase until prime */
+  newsize |= 0x1; 
+  while (!ei_isprime(newsize)) newsize +=2;
+
+  if (newsize == oldtab->size) return oldtab;
+  
+  /* make a new table */
+  if (!(newtab = ei_hash_newtab(newsize))) return oldtab;
+  newtab->hash = oldtab->hash;
+
+  /* move the buckets, rehashing */
+  /* note that this will reverse the order of any chains */
+  for (i=0; i<oldtab->size; i++) {
+    b=oldtab->tab[i];
+    while (b) {
+      next = b->next;
+      h = b->rawhash % newtab->size;
+      b->next=newtab->tab[h];
+      if (!newtab->tab[h]) newtab->npos++;
+      newtab->tab[h]=b;
+      b = next;
+    }
+  }
+  /* the new table has the same number of elements as the old one */
+  newtab->nelem = oldtab->nelem;
+
+  /* the new table takes over the freelist from the old one */
+  newtab->freelist = oldtab->freelist;
+
+  /* now it's safe to remove the old table */
+  free(oldtab);
+
+  return newtab;
+}
-- 
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